Oh my! Not again!

If what you get is really what you describe, then do yourself (and your text-in-pointy-brackets provider) a favor: don't call it XML. And write (or have your povider write) a hundred times "If it does not parse, then it is NOT XML" Whether the reason is messed up tags, an encoding problem or anything else, they have no business calling it XML if an XML parser doesn't say that it is well-formed.

Once you have realized this, it then makes sense that, as you are not processing XML, you cannot use XML tools. At least not directly You need first to convert the data you get into real XML, or even better, have the source provide real XML, make sure it is OK by parsing it, and then you can use an XML module.